Due to the needs for enhancing fuel efficiency of vehicles and satisfying stricter exhaust gas regulations, various environmentally-friendly vehicles are being developed.
A mild hybrid vehicle is mounted with an ISG (integrated starter and generator) in order to start an engine and support driving power, and either a DCT (Double Clutch Transmission) or an AMT (Automated Manual Transmission) is applied as a transmission.
General mild hybrid vehicles minimize fuel consumption by stopping operation of the engine and releasing engagement of the transmission when the vehicle is coasting.
However, since fuel is not injected into the engine while the mild hybrid vehicle is coasting, temperature of a combustion chamber may decrease. When the engine of the vehicle is operated after a temperature of the combustion chamber is decreased, since the temperature of the combustion chamber is low, it is difficult to ensure combustion stability.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.